1. Field of the Invention
The present invention relates to apparatus and methods for removal of heat from electronic devices. In particular, the present invention relates to a fluid circulation pump in conjunction with a heat sink for the removal of heat from a microelectronic die.
2. State of the Art
Higher performance, lower cost, increased miniaturization of integrated circuit components, and greater packaging density of integrated circuits are ongoing goals of the computer industry. As these goals are achieved, microelectronic dice become smaller. Accordingly, the density of power consumption of the integrated circuit components in the microelectronic die has increased, which, in turn, increases the average junction temperature of the microelectronic die. If the temperature of the microelectronic die becomes too high, the integrated circuits of the microelectronic die may be damaged or destroyed.
Various apparatus and techniques have been used and are presently being used for removing heat from microelectronic dice. One such heat dissipation technique involves the attachment of a high surface area heat sink to a microelectronic die. FIG. 5 illustrates an assembly 200 comprising a microelectronic die 202 (illustrated as a flip chip) physically and electrically attached to a substrate carrier 204 by a plurality of solder balls 206. A heat sink 208 is attached to a back surface 212 of the microelectronic die 202 by a thermally conductive adhesive 214. The heat sink 208 is usually constructed from a thermally conductive material, such as copper, copper alloys, aluminum, aluminum alloys, and the like. The heat generated by the microelectronic die 202 is drawn into the heat sink 208 (following the path of least thermal resistance) by conductive heat transfer.
High surface area heat sinks 208 are generally used because the rate at which heat is dissipated from a heat sink is substantially proportional to the surface area of the heat sink. The high surface area heat sink 208 usually includes a plurality of projections 216 extending substantially perpendicularly from the microelectronic die 202. It is, of course, understood that the projections 216 may include, but are not limited to, elongate planar fin-like structures and columnar/pillar structures. The high surface area of the projections 216 allows heat to be convectively dissipated from the projections 216 into the air surrounding the high surface area heat sink 208. A fan 218 may be incorporated into the assembly 200 to enhance the convective heat dissipation.
Although high surface area heat sinks are utilized in a variety of microelectronic applications, they have not been completely successful in removing heat from microelectronic dice that generate substantial amounts of heat. Therefore, it would be advantageous to develop apparatus and techniques to effectively remove heat from microelectronic dice.